Fuel cell stack and assembling method of fuel cell stack

Abstract

A fuel cell stack including a cell stacked body including power generation cells, a housing surrounding the cell stacked body, and a fixed member fixed to the housing to face an outer surface of the cell stacked body. Each of the power generation cells includes a unitized electrode assembly including a membrane electrode assembly and a frame member having a flexibility and supporting an edge portion of the membrane electrode assembly, and a separator disposed to face the unitized electrode assembly to form a flow path between the separator and the unitized electrode assembly, an edge portion of the frame member includes a protruding portion protruding outward from an edge portion of the separator, and the protruding portion includes a bent end portion bent toward the edge portion of the separator and sandwiched between the fixed portion and the edge portion of the separator.

What is claimed is: 
     
         1 . A fuel cell stack comprising:
 a cell stacked body including a plurality of power generation cells;   a housing surrounding the cell stacked body; and   a fixed member fixed to the housing so as to face an outer surface of the cell stacked body, wherein   each of the plurality of power generation cells includes:
 a unitized electrode assembly including a membrane electrode assembly having an electrolyte membrane and an electrode, and a frame member having a flexibility and formed to support an edge portion of the membrane electrode assembly; and 
 a separator disposed to face the unitized electrode assembly so as to form a flow path in which a reaction gas flows between the separator and the unitized electrode assembly, 
   an edge portion of the frame member includes a protruding portion protruding outward from an edge portion of the separator, and   the protruding portion includes a bent end portion bent toward the edge portion of the separator and sandwiched between the fixed portion and the edge portion of the separator.   
     
     
         2 . The fuel cell stack according to  claim 1 , wherein
 the cell stacked body is configured by stacking a plurality of cell units, and   each of the plurality of cell units includes the unitized electrode assembly and the separator joined to each other at a joining portion.   
     
     
         3 . The fuel cell stack according to  claim 1 , wherein
 the separator includes a first protruding portion protruding toward the frame member and a second protruding portion protruding in a direction away from the frame member,   the protruding portion is bent toward the edge portion of the separator, the edge portion of the separator being located away from the frame member, and   the bent end portion is sandwiched between the fixed member and the edge portion of the separator.   
     
     
         4 . The fuel cell stack according to  claim 3 , wherein
 the separator includes a pair of plate members joined to each other,   the first protruding portion is formed in one of the pair of plate members, and   the second protruding portion is formed in another of the pair of plate members.   
     
     
         5 . The fuel cell stack according to  claim 1 , wherein
 the fixed member is a guide member configured to position the plurality of power generation cells with respect to the housing, and   the edge portion of the separator is configured to engage with or fit to the guide member through the bent end portion.   
     
     
         6 . The fuel cell stack according to  claim 5 , wherein
 each of the frame member and the separator includes a recessed portion in which the guide member is fitted.   
     
     
         7 . The fuel cell stack according to  claim 6 , wherein
 the separator includes a rib provided around the recessed portion.   
     
     
         8 . An assembling method of a fuel cell stack, comprising
 joining a unitized electrode assembly and a separator disposed to face the unitized electrode assembly to form a cell unit, the unitized electrode assembly including a membrane electrode assembly and a frame member having a flexibility and formed to support an edge of the membrane electrode assembly, the membrane electrode assembly having an electrolyte membrane and an electrode, the separator being configured to form a flow path in which a reaction gas flows between the separator and the unitized electrode assembly; and   stacking a plurality of the cell units while abutting on a fixed member fixed to a housing to form a cell stacked body, wherein   the stacking includes stacking the plurality of the cell units while bending an edge portion of the frame member protruding outward from an edge portion of the separator toward the edge portion of the separator and sandwiching the edge portion of the frame member between the fixed member and the edge portion of the separator.